Medicine: It's A Girl!

Picking an embryo's sex prevents the inheritance of some diseases

Many prospective parents would love to choose the sex of their child. That is now possible, according to a report last week in Nature. But the technique, developed by Dr. Alan Handyside at Hammersmith Hospital in London, is far from simple. It involves creating several test-tube embryos outside the mother's womb through in vitro fertilization. Handyside's team found a way to determine the sex of embryos that are only a few days old by analyzing their genetic material. An embryo of the desired sex can then be implanted in the womb and the other embryos discarded.